A conventional air bag mounting structure for a passenger-side air bag device (e.g. JPA H07-69157) will be described with reference to FIGS. 5 and 6. An inflator 12 is arranged in a rear portion (the innermost portion) of a retainer 10. A passenger-side air bag 14 is provided with four flaps 18, 20, 22, 24 arranged around a gas inlet 16 of the air bag 14. The edge portions of flaps 18-24 are turned up and sewn on the respective lapped portions of the flaps so as to form narrow saccate portions 18a, 20a, 22a, and 24a. Numeral 26 designates seams.
Plates 28, 30 are inserted into the respective saccate portions 18a-24a. The plates 28, 30 are each provided with rivet holes 32 formed therein. The flaps 18-24 of the air bag 14 and the retainer 10 are also provided with rivet holes 34 formed in the same arrangement of the rivet holes 32.
The saccate portions 18a-24a with the plates 28, 30 therein are brought in contact with the inner surfaces of the front portion of the retainer 10 and fastened together by blind rivets 38. In this way, the air bag 14 is fixed to the retainer 10 as shown in FIG. 6.
In this conventional structure in a passenger-side air bag device, there are spaces C between the adjacent flaps 18-24. Therefore, there is a possibility of gas leaking from the spaces C when the inflator 12 is activated. For this, it is required to employ a large-capacity inflator as the inflator 12 for compensating for the amount of gas to be leaked.